Telephonic receiver.



3A.. MARR. -Y TELEPHONIO EEGEIVBB.

APPLIUATION FILED JAN. 8, 1913.'

Patented Feb.'17,' 1914 mmnnmnn'. or wraircrmsrnn,Y nNeLann.

TELEPHONE nncnrvnn..

Spe'cication of: LetYtersPatent.

Patented Feb. 17, 1914..

Applicationiled January 8, 1913. Serial No. 740.837.

To all whom t may concern B'e it known'that I5 ALEXANDER MARR, a subjectof the King of Great Britain and Ireland, and a. resident of-Manchester, England, have invented new and useful Improvements 1nTelephonie Receivers, of

which the following is a specification.

This invention relates to improvements in that type of telephoniereceiver (generally known as the 'IVestern `Electric type) in which theupper ends of the two limbs of a magnet are combined with a brass orother non-magnetic cup which contains the pole pieces. In such aninstrument as at present commonly made the ends of the magnet abutagainstthe lower face of the brass or other cup, and the pole pieces aremagnetically and mechanically connected to .the ends of the limbs of themagnet by means of iron screws from the pole pieces passing through thebrass cup and screwing into.

holes tapped in the ends'of -the magnet limbs:

In a receiver constructed to embody my improvements there are no screwsentering into the ends of the magnet limbs and the ends of these limbs(or extensions thereof) vpass through the substance of the brass cup andare iiush with or project slightly above the inner surface of the-cup.They are held in position relatively tothe cup by a screw which passesdown through the cup and engages with a packing member of vulcanizedfiber .or other non-magnetic material contained and held between thelimbs of the magnet or being otherwise combined with or -secured totheir ends. This liber, or shou1` ders formed on the ends of the magnetlimbs, or the ends of such limbs themselves limits or limit the movementof the cup toward or along the magnet 'limb ends and forms or form aseat orseats for the cup.

:The pole pieces are then laid on the ends of the magnet limbs or .theextensions thereof on the inner face of the cup and are secured byscrews engaging with the cup. These screws may be of magnetic metal andin the case of extensions only from the magnet ends passing through thebrass cup, their ends may abut against the magnet ends or againstshoulders on such ends. By this construction all boring and tapping ofthe' magnet ends for the purpose of securlng them to the brass cup isavoided. The extensions may be integral with the magnets or they may beseparate iron or steel disks Vof the cup to the inner or upper face ofthe cup.

The accompanying drawings illustrate two modifications in the. meansfor" combining the brass cap, the pole pieces7 and the magnet endsaccording to this invention. In the modication shown in Figs. l o 4inclusive the extensions of the magnet are separate iron disks. In themodiiication shown in Figs. 6 and 7 the extensions of the magnet areintegral with its limbs.

Fig. 1- is a longitudinal section of an improved receiver. Fig. 2 is anend view of such receiver with the cap removed. Fig. 3 is a crosssectional viewv across the cup with the pole pieces removed. Fig. 4 is asectional elevation of parts of the same the magnet limbs and the liberbetween them. Fig. 6 is a sectional elevation of parts .of a receiverthe magnet of which has extensions which areintegral with its limbs.Fig. 7 is an end view of the parts of Fig. b with the pole piecesremoved.

A indicates the casing or' .the instrument; B the screw cap; C C themagnet limbs; .D the brass `or non-magnetic cup; E El the magnet polepieces, and F the diaphragm which is clamped between the screw cap B andthe edge or rim of the cup D.

According to this invention a strip or bar G of vulcanized fiber orother suitable nonmagnetic substance is contained between the magnetlimbs C C1. This bar G and the limbs C C1 are rigidly secured togetherby the magnetic cross piece and distance mem- -ber C2 by which the limbsC C1 are magnetically connected and which passes through the bar G nearto one end. The other end of the bar G is bored'and tapped for a screwH. In the form of instrument shown in Figs. l to 4 the ends of the limbsC C1 andthe bar G are all level or iush with one another at lthat end ofthe combined magnets and bar where the latter is screwed. By passing thescrew I-I down through the center of the cup D and screwing it into thebar G- as shown in Fig. 1 the ends of the magnet limbs can be drawntightly up against the under face of the cup.' The' combined bar G andmagnet limbs are circular in cross section and their combined ends fitsnugly within the circular wall D1 formed on the lower face of thecepa-Iv Thecup perforated with two round holes J J one over the end ofcach 4magnet linibf E' Within each hole is placed.

`an iron diskdl J1 each of a size and thick ness to restiipon the end ofthe magnet vand reach Bush to or slightly above the inner sur- .face ofthe cup. With the disks so in place the magnet pole pieces E .El arescrewed down, one over each disk, on to the inner face oit' the cup bymeans of screws K Kengaging with holes K1 in the met-al of the cup. Thedisks Pact as magnetic. conducpieces.

' the magnet, will permit magnetic flux.

In the' modification shown in Figs. 6 and T the disks J1 are dispensedwith and are substituted by projections J2 from the ends.

of the magnet limbs C C1 which similarly occupy and pass through holes Jin the cup and project to or slightly beyond the inner surface of thecup. The pole pieces E El are then screwed down on to them..

The sides of the fiber bar or strip may be formed with longitudinalgrooves G1 along which the wires L are led'to the coils on the polepieces, such wires entering the cup .through holes M.

N N are screws or terminals on the end of the strip G to .which screwsthe described wires are connected as are also `the ends of the flexibleWires P.

"What I claim is .1.J in a telephonie. receiver, a U-shaped inem-iestween the limbs thereof, a non-magnetic cup magnet7 a nonnenagneticV barextending beextending across the ends of said magnetl and bar, ascrewwhich passes through'the bottom of said cup into theend of said bar,

magnetic extensions of the magnet passing through the bottom 'of thecup,` and polev pieces which are secured tothe cup and on to themagnetic extensions.

2. In a telephonie receiver, a magnet; a

non-magnetic bar combined therewith, a

-nonfmagnetic cup, a screw which screws the non-magnetic cup tothenonunagnetic bar,'

loose iron disks placed in perforations of the cup and in contact withthe magnete-nds, and .pole pieces screwed down to the cup and on to theiron disks, substantially as set forth.

3. In a telephonie receiver, the Gombina tion with a magnet comprisingtwo parallel limbs and a nonmagneticbar clamped between them and formingtherewith a cylindrical structure, of a nonmagnetic cup having acircular wall lfitting. over the end of said magnet, a screw passingYthrough said cup into the end of said bar, and pole pieces lcarriedinside said cup in line with the ends ot said magnet limbs.

` In Witness whereof I have hereunto set my hand 1n the presence of twosubscribing Wit- 65 nesses.

- ALEXANDER MARR. Witnesses:

WILIJAM GEO. HEYS, JOHN UCONNELL.

